DAViCal

Simple calendar and contact server with extremely low administrative overhead.

Lightweight CalDAV and CardDAV server based on sabre/dav.

End-to-end encrypted and journaled personal information server supporting calendar and contact data, offering its own clients.

Open source CardDAV, CalDAV, and WebDAV framework and server.

POP/IMAP/SMTP/Caldav/Carddav/LDAP exchange gateway allowing users to use any mail/calendar client with an Exchange server, even from the internet or behind a firewall through Outlook Web Access.

Open source CardDAV and CalDAV server with minimal administrative overhead, backed by a Git repository.

A simple, dockerizable and fully translatable admin interface for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal.

Manage my Damn Life (MMDL) is a self-hosted front end for managing your CalDAV tasks and calendars.

EteSync's official Web-based client (i.e., their Web app).